Inorganic-organic compositions

ABSTRACT

Inorganic-organic compositions obtained from a mixture of components comprising:

This invention relates generally to synthetic materials and moreparticularly to an improved inorganic-organic material formed, generallyspeaking, by reacting an organic polyisocyanate with an aqueous solutionof an alkali metal silicate optionally also with a water-bindingcomponent present.

It is known that polyurethane or polyurea plastics can be produced fromorganic polyisocyanates and compounds containing active hydrogen atomswhich react with -NCO groups. The properties of this class of polymersvary widely. High strength, elasticity and abrasion resistance areparticularly valuable properties of these products. On the other hand,their heat stability and in particular their permanent dimensionalstability at temperatures above 120° C are only moderate. The use ofthese products as building and structural elements is limited on accountof their unfavorable flame resistance. Although their flame resistancecan be improved through the incorporation of flame proofing agents,their mechanical properties are generally adversely affected in thisway.

It is also known that inorganic silica-gel materials can be preparedfrom aqueous solutions of alkali silicates by the action of acids orprecursors of acids such as anhydrides. Materials of this kind haveacquired particular significance as adhesives, surface-coatings and thelike. Lightweight foams have also been produced on the basis of waterglass. Products such as those show high dimensional stability under heatand are completely non-inflammable. However, they are brittle and offairly limited strength. As foams they have no real load-bearingcapability and crumble under pressure. It would be extremely desirableto combine with one another the favorable properties of the inorganicmaterials and of organic plastics materials and to eliminate theundesirable properties of both.

Accordingly, there has been no shortage of attempts to produce compositeplastics although none of these attempts has ever reached the requiredobjective.

For example, polyurethanes have been mixed with active silica as afiller and subsequently the resulting mixture has been vulcanized as inU.S. Pat. No. 3,395,129. There are some signs in this case of astrengthening effect, as in cases where highly active carbon black isused. The tensile strength and the modulus increase while the breakingelongation decreases. However, the basic property spectrum of thematerial is not affected by the use of silica, probably because there isa two-phase system in which only the polyurethane forms a coherent phasewhile the silica is incorporated therein as an incoherent phase. Theincoherent zones have diameters of the order of 3 to 100 microns.Accordingly, the known two-phase systems are relatively coarse,heterogeneous two-phase systems. The interaction between the two phasesis very limited both on account of the relatively small interface andbecause of the very different chemical nature of the two phases.

It is also known to use silica in plastics in the form of microfibers.In this case, the strengthening effect increases by virtue of thespecific structure although, on the other hand, the incoherent phaseinevitably become larger so that the chemical interaction between thetwo phases decreases. But none of the foregoing alters the coarseheterogeneous two-phase character of the plastic.

In addition, it has been proposed in U.S. Pat. No. 3,607,794 to react anaqueous solution of an alkali silicate with a monomeric polyisocyanate,for example, 4,4'-diphenylmehane diisocyanate. In most cases, thisreaction gives foams in which the isocyanate phase reacts with the waterand the carbon dioxide formed foams the mass, some of the carbon dioxidereacting only with the immediately adjacent aqueous silicate phase togive some gel formation but inadequate penetration to give completeuniform gelling.

The reaction is preferably carried out with a predominant quantity ofwaterglass so that a mixture is formed which is an emulsion of theisocyanate in a coherent silicate solution. Accordingly, the resultingfoam is in character a silicate foam which contains incoherent foamedpolyurea zones. The properties of a foam of this kind are not really anydifferent from those of a pure silicate foam. In fact, foams produced inthis way have the disadvantage of being generally highly waterretentive, brittle and of insufficient mechanical strength for theirgross density to be suitable for use as construction materials forexample, foam concrete.

Although the organic polyisocyanate which is added to the silicatesolution acts as hardener, it has little effect upon the properties ofthe foam formed. Any effect it may have is frequently a negative effect.Obviously, in the final product the organic portion is presentsubstantially as a filler in the completed silicate skeleton.

On the other hand, when an excess of polyisocyanate is used in theprocess of U.S. Pat. No. 3,607,794 polyurea foams containing a dispersedincoherent silicate phase are obtained. Accordingly, the properties aresubstantially those of a silica-filled polyurea foam with highflammability and extreme brittleness.

If the teaching of U.S. Pat. No. 3,607,794 is followed, it can be seenthat mixtures of aqueous silicate solution and oganic polyisocyanatesform only relatively coarse-particle emulsions. Although hisdisadvantage can be reduced to a large extent by the recommended use ofsurfactants which make the primary emulsions more finely divided andstable, the property spectrum still remains unsatisfactory. While thesurfactants effect a reduction in particle size, the use of surfactantsleads to poor compression strength in the final products. In particular,composite materials obtained show pronounced brittleness and limitedcompression strength. It must be concluded from the results hithertoobtained that composite foams of silicates and organic materials do nothave any decisive advantages over pure organic or pure inorganicmaterials.

It has been also proposed in French Pat. Nos. 1,362,003 and 1,419,552 touse polyisocyanates, alkali metal silicates and polyether or polyesterresins to make foams but the resulting rigid products, like thoseproduced in accordance with U.S. Pat. No. 3,607,794 are brittle and havelow compression strength. Flexible products made in accordance withthese French patents have poor tensile strength.

It is also known that aggregates can be produced from mineral granulesand synthetic resins. Processes for producing synthetic resin concretefrom porous mineral materials and mixtures which are capable of foamingare known in the art (German Auslegeschrift No. 1,239,229).

In these cases, the mineral material is always included within andbonded together by synthetic resin. Synthetic resin concretes producedin this way have, however, the disadvantages of not being homogeneous sothat they are subjected to different degrees of mechanical stress indifferent zones. Moreover, it is often necessary to use considerablequantities of more than about 30% by weight of an organic syntheticresin which is not only expensive but which also, in most cases, reducesthe flame resistance.

It is already known that concrete conventionally used for buildingpurposes can be diluted by the addition of organic porous syntheticresins such as foamed polystyrene and it is also known to add blowingagents such as air to concrete mixtures or to produce gases in situ byadding, for example, aluminum which evolves hydrogen by reactions withthe water-cement mixture, in order to obtain porous materials with lowgross densities.

The disadvantages of those substantially inorganic materials arerelatively long setting times, their relatively high brittleness andtheir low thermal insulation, compared with organic foam structures.

It is also known to produce structural elements from porous organicsynthetic resins with solid, fire-resistant covering layers which are inmost cases inorganic or metallic.

Owing to their organic nature, these materials have the disadvantagethat they cannot be used as building materials without fire-retardingcovering layers.

It is also known to produce cement masses from hydraulic cement, anon-aqueous silica filler such as sand and an organic compound whichcontains a plurality of isocyanate groups (German OffenlegungsschriftNo. 1,924,468). The main disadvantages of these porous cement masses isthat they still have comparatively long setting times of 5-6 hours andpoor thermal insulation properties.

Heat-resistant foams can be obtained from thermoplastic synthetic resinswhich can be foamed or are already cellular by working them up in thepresence of aqueous alkali metal silicate solutions (GermanAuslegeschrift No. 1,494,955). The disadvantages of this process are thelarge heat supply required to foam the thermoplastic resin, the problemof hardening the alkali metal silicate solutions and the water contentof the resulting composite material.

It is an object of the invention to provide improved inorganic-organiccompositions which are devoid of the foregoing disadvantages. Anotherobject of the invention is to provide inorganic-organic compositions ofhigh strength, rebound elasticity and dimensional stability even at hightemperatures which are substantially non-inflammable.

A more specific object of the invention is to obviate the abovedescribed disadvantages of known foam materials and to produce anorganic-inorganic foam material which combines the advantages of rapidsetting times, high compression strength compared to the gross density,high thermal and acoustic insulation, high-flame resistance andexcellent resistance to fire.

A still more specific object of the invention is to provide improvedthermal and acoustic insulation materials from cheap and readilyavailable raw materials which have low densities of between 8 kp/m³ -80kp/m³, high flame-resistance and low smoke density when exposed to fire.

The foregoing objects and other which will become apparent from thefollowing description are accomplished in accordance with the invention,generally speaking, by providing an inorganic-organic compositionobtained from a mixture of components comprising:

a. from 5-98% by weight of an organic, non-ionic hydrophilicpolyisocyanate, and

b. from 2-95% by weight of an aqueous alkali metal silicate solutioncontaining about 20-70% by weight of said alkali metal silicate, basedon the total weight of (a) and (b).

Thus, a product and process, therefore, has now been found by which itis possible to produce macroscopically completely homogeneousinorganic-organic compositions which are xerosol materials of thesolid/solid type, similar to the known ABS-plastics, in their colloidalnature, but have entirely different properties. Xerosols are dispersionsof solid or liquid materials in a coherent solid. The completely newcomposite materials obtained in this way are extremely high-qualitycompositions which are advantageously distinguished in their propertiesfrom pure organic or pure inorganic materials. They are distinguished inparticular, by high strength, rebound elasicity, insulating properties,dimensional stability under heat and substantial non-inflammability.

It has surprisingly been found that these inorganic-organic materials ofhigh strength, rebound elasticity, dimensional stability when heated andsubstantial non-inflammatility can be obtained by homogeneously mixingsaid polyisocyanate with said aqueous solutions of alkali silicates, ifrequired with an appropriate amount of a water-binding component orfiller present, and allowing the sol formed to react to form a xerosol.The colloidal dispersion and mutual penetration of the two phases isbelived to be an essential criteria, making possible high specificsurface and interfacial interactions such as are characteristic ofxerosols. Best properties are obtained with the organic phase beingcontinuous.

The invention also contemplates an improvement in the flame resistanceeven beyond that which is possible with only components (a) and (b) asset forth above. Thus when only (a) and (b) are combined a product isobtained which is not entirely stable in a fire. Under a direct flame,the waterglass has a tendency to exude from the material and even tomelt and fall out of the composition so that the supporting inorganicstructure is completely lost.

It is also a feature of the invention that by adding a halogen orphosphorus containing compound one can improve the flame resistance ofinorganic portions of the material. It is also an advantage of theinvention that the added components have no detrimental effect on theproduct but they do react at temperatures above about 400° C to form areaction product with the sodium carbonate with the evolution of carbondioxide which helps to extinguish the flame. In many instances othercompounds including e.g. sodium choride, sodium bromide, sodiumphosphate and the like result, and these compounds cannot react furtherwith the silica dioxide, so the product remains very resistant to flame.Thus, when this particular embodiment is used one obtains productssuitable for the production for, for example, the wall of building, thathas greatly enhanced burn through resistance; that is when a flame isdirected to the broad side of a wall, immediately further flameresistant reaction products result from a high temperature reaction ofthe halogen or phosphorus compound with the sodium carbonate to not onlyextinguish the flame, but also to prevent further flame spread.

We are not certain of the mechanism of the invention but is is apparentthat products without the added halogen or phosphorus containingcompound suffer from a reaction between the sodium carbonate formedduring the process with the silica dioxide so that waterglass which hasa very low melting point is reformed. The resulting composition has poorcompression strength and dimensional stability in a fire. On thecontrary, a product with vastly improved compression strength anddimensional stability is obtained with the added halogen or phosphoruscontaining compound.

Further, with the added halogen or phosphorus in even very intense heatso that the organic phase is completely consumed, there remains a fireresistant self-supporting inorganic foam. Also there is no evolution oftoxic gases such as, HCl or HBr because other non-toxic products suchas, NaCl or NaBr are formed.

Suitable flame resistant compounds which contain halogen or phosphorusare e.g. tributylphosphate, tris-(2,3-dichloropropyl)-phosphate,polyoxypropylenechloromethylphosphonate, cresyldiphenylphosphate,tricresylphosphate, tris-(β-chloroethyl)-phosphate,tris-(2,3-dichloropropyl)-phosphate, triphenylphosphate,ammoniumphosphate, perchlorinated diphenyl, perchlorinated terephenyl,hexabromocyclodecane, tribromophenol, dibromopropyldiene,hexabromobenzene, octabromodiphenylether, pentabromotoluol,poly-tribromostyrol, tris-(bromocresyl)-phosphate, tetrabromobisphenolA, tetrabromophthalic acid anhydride, octabromodiphenyl,tris-(dibromopropyl)-phosphate, calcium hydrogen phosphate, sodium orpotassium dihydrogen phosphate, disodium or dipotassiumhydrogenphosphate, ammoniumchloride, phosphoric acid, polyvinylchloridetelomers, chloroparaffins as well as further phosphorus and/or halogencontaining flame resistant compounds as they are described e.g. in"Kunststoff-Handbuch," Volume VII, Munich 1966, pages 110-111 which isincorporated herein by reference. The organic halogen containingcomponents are, however, preferred.

By using the organic polyisocyanate containing non-ionic hydrophilicgroups including, for example, isocyanato prepolymers i.e., polyureapolymer precursors containing non-ionic hydrophilic groups, it ispossible to obtain such a homogeneous dispersion of the organic andaqueous inorganic phases that sols are formed in which the dispersephase is present in dimensions of from about 20 nanometers (nm) to 2microns, preferably from 50 nm to 700 nm, so that the chemicalinteractions increase by orders of magnitude and novel compositematerials are obtained. In particular, it is also possible by using thepolyisocyanates containing non-ionic hydrophilic groups to obtain acolloidal fiber structure so that both phases can be present as coherentsystems. This means that a macroscopically and, in many cases, even amicroscopically homogeneous composite material is obtained whichcombines the advantages of inorganic and organic compositions.

Accordingly, the present invention also relates to a process for theproduction of said inorganic-organic compositions compositions of highstrength, rebound elasticity, dimension stability even when hot andsubstantial non-inflammability which is a polyurea-polysilicic acid gelcomposite material in the form of a colloidal xerosol, wherein anaqueous silicate solution is combined with

a. an organic non-ionic, hydrophilic polyisocyanate,

b. a water-binding component (i.e. another compound which hardens thewater-soluble silicates), in the amounts and with proviso set forthabove, and

c. optionally further auxiliaries and additives, and the system thusobtained is allowed to react to completion.

The non-ionic-hydrophilic isocyanates which are used for the processaccording to the invention may be prepared by known methods, e.g. byreacting organic hydroxyl compounds which have a molecular weight ofabout 400 to about 5000, in particular mono- or polyhydroxyl polyethers,optionally mixed with polyhydric alcohols which have a molecular weightbelow about 400, with an excess of organic polyisocyanate.

Any suitable organic polyisocyanate may be used. The average molecularweight of the organic polyisocyanate should preferably be between 300and 8000 (most preferably between 400 and 5000). Suitablepolyisocyanates include aliphatic, cycloaliphatic, araliphatic, aromaticor heterocyclic polyisocyanates such as those described e.g. by W.Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, forexample, ethylene diisocyanate; tetramethylene-1,4-diisocyanate;hexamethylene-1,6-diisocyanate; dodecane-1,12-diisocyanate;cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and 1,4-diisocyanate andany mixtures of these isomers;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (GermanAuslegeschrift No. 1,202,785); hexahydrotolylene-2,4- and-2,6-diisocyanate and any mixtures of these isomers;hexahydrophenylene-1,3- and/or 1,4-diisocyanate,perhydrodiphenylmethane-2,4'- and/or -4,4'-diisocyanate; phenylene-1,3-and -1,4-diisocyanate; tolylene-2,4- and -2,6-diisocyanate and anymixtures of these isomers; diphenylmethane-2,4'- and/or-4,4'-diisocyanate; naphthylene-1,5-diisocyanate;triphenylmethane-4,4',4"-triisocyanate;polyphenyl-polymethylene-polyisocyanates which may be obtained byaniline-formaldehyde condensation followed by phosgenation and whichhave been described e.g. in British Pat. Specification Nos. 874,430 and848,671; perchlorinated aryl polyisocyanates such as those describede.g. in German Auslegeschrift No. 1,157,601; polyisocyanates whichcontain carbodiimide groups as described in German Patent SpecificationNo. 1,092,007; the diisocyanates described in U.S. Pat. SpecificationNo. 3,492,330, polyisocyanates which contain allophanate groups asdescribed e.g. in British Pat. Specification No. 994,890; Belgian Pat.Specification No. 761,626 and published Dutch Pat. application No.7,102,524; polyisocyanates which contain isocyanurate groups asdescribed e.g. in German Pat. Specification Nos. 1,022,789; 1,222,067and 1,027,394 and in German Offenlegungsschriften Nos. 1,929,034 and2,004,048; polyisocyanates which contain urethane groups as describede.g. in Belgian Pat. Specification No. 752,261 or in U.S. Pat.Specification No. 3,394,164; polyisocyanates which contain acylated ureagroups in accordance with German Pat. Specification No. 1,230,778;polyisocyanates which contain biuret groups as described e.g. in GermanPat. Specification No. 1,101,394; in British Pat. Specification No.889,050 and in French Pat. Specification No. 7,017,514; polyisocyanatesprepared by telomerization reactions as described e.g. in Belgian Pat.Specification No. 723,640; polyisocyanates which contain ester groups asdescribed e.g. in British Pat. Specification Nos. 965,474 and 1,072,956;in U.S. Pat. Specification No. 3,567,763 and in German Pat.Specification No. 1,231,688 and reaction products of the above mentionedisocyanates with acetals in accordance with German Pat. SpecificationNo. 1,072,385.

The distillation residues which still contain isocyanate groups obtainedfrom the commercial production of isocyanates are preferred, and may bedissolved in one or more of the above mentioned polyisocyanates. Anymixtures of the above mentioned polyisocyanates may also be used.

It is generally preferred to use commercially readily availablepolyisocyanates such as polyphenyl-polymethylene-polyisocyanatesobtained by aniline-formaldehyde condensation followed by phosgenation("crude MDI") and polyisocyanates which contain carbodiimide groups,urethane groups, allophanate groups, isocyanurate groups, urea groups orbiuret groups ("modified polyisocyanates").

The isocyanate group can also be present in masked form, for example, asa uretdione or caprolactam adduct. The polyisocyanates used in theprocess according to the invention preferably contain from about 2 to 10more preferably from 2.2 to 4 isocyanato groups.

Suitable organic polyisocyanates also include prepolymers obtained bythe so-called isocyanate-polyaddition process of the kind which havebeen repeatedly described over recent years. It is no problem to controlvirtually any known isocyanate reaction so that it can be stopped atleast temporarily at a prepolymer stage. The prepolymers include notonly adducts of polyisocyanates with alcohols, mercaptans, carboxylicacids, amines, ureas and amides, but also reaction products of theforegoing polyisocyanates with themselves, such as, uretdiones,isocyanurates, carbodiimides which can readily be obtained frommonomeric polyisocyanates with an increase in molecular weight.

NCO-prepolymers particularly suitable for the process according to theinvention are prepared by methods known per se, for example, by reactingpolyhydroxyl compounds with a molecular weight of from about 400 to5000, more especially polyhydroxyl polyesters and polyhydroxypolyethers,if desired in admixture with polyhydric alcohols with a molecular weightof less than 400, with excess quantities of polyisocyanates, forexample, hexamethylene diisocyanate, 2,4-tolylene diisocyanate,2,6-tolylene diisocyanate, 4,4'-diisocyanatodiphenylmethane, etc.

Non-ionic hydrophilic modification of the prepolymer may be achieved,for example, by reacting a polyisocyanate with a hydrophilic polyetherwhich contains groups which are reactive with isocyanate groups or witha siloxane compound which contains hydrogen atoms which are reactivewith isocyanate groups. Polyethers which have been synthesized fromalcohols with a functionality of 1 to 3 and ethylene oxide/or propyleneoxide and which contain terminal OH groups are preferred although othercompounds containing polyether or polyether groups which have beenprepared by different methods, may of course, be used in preparing theprepolymer provided such compounds contain hydrophilic groups. It isparticularly preferred to use monofunctional polyethers based onmonoalcohols with a molecular weight of about 32 to about 300 ethyleneoxide because the non-ionic hydrophilic prepolymers prepared from thesestarting materials generally have a viscosity of less than 50,000 cP,which is advantageous for working up, and preferably less than 10,000cP.

The reaction products of the above mentioned polyisocyanates withaliphatic polycarbonates which contain hydrogen atoms which are reactivewith isocyanate groups are also suitable prepolymers for the purpose ofthe invention. Examples of such prepolymers are polycarbonates based onethylene glycol, propylene glycol or tetraethylene glycol. Prepolymerswhich contain a hydrophilic polyether segment, e.g. of triethyleneglycol or diethylene glycol and succinic acid or oxalic acid are alsosuitable. These segments may be destroyed in the course of thesubsequent reaction with waterglass in which the inorganic componenthardens and the organic component becomes hydrophobic.

The hydrophilic center may also be introduced by incorporating a glycolsuch as triethylene or tetraethylene glycol, preferably in combinationwith a very hydrophilic isocyanate such as a biuret diisocyanate orbiuret triisocyanate.

The hydrophilic groups may be present in the main chain or the sidechain of the prepolymer.

In addition to the hydrophilic-non-ionic segment, there may also be anionic center either in the same or some other molecule. Suchionic-non-ionic combinations enable the morphology and interfacechemistry of the two-phase plastics of the invention to be adjusted asdesired.

If desired, prepolymers known per se and particularly those based onaromatic isocyanates may also be subsequently reacted by the processesmentioned above to produce non-ionic hydrophilic prepolymers.

Particularly suitable prepolymers which have a high stability in storagecan also be obtained by reacting aromatic isocyanates such as tolylenediisocyanate, diphenylmethane diisocyanates and the known phosgenationproducts of the products of condensation of armoatic monoamines such asaniline and aldehydes such as formaldehyde with hydrophilic polyetherswhich contain groups which are reactive with isocyanates. Thesenon-ionic hydrophilic polyisocyanates which according to IRspectroscopic analysis in part still contain detectable urea and biuretgroups as well as urethane and/or allophanate groups in cases wherepolyol modification has been carried out are eminently suitable asprepolymers.

The phosgenation products used for non-ionic hydrophilic modificationare preferably products of the phosgenation of higher molecular weightaniline/formaldehyde condensation products which have a viscosity at 25°C of about 50 to 10,000 cP, preferably 100-5000 cP.

Reaction products of 50-99 mols of aromatic diisocyanates and 1-50 molsof the usual organic compounds which contain at least two hydrogen atomscapable of reacting with isocyanates and generally have a molecularweight of about 400 to about 10,000 may also be used. Apart fromcompounds of this kind which contain amino groups, thiol groups orcarboxyl groups, these compounds are preferably polyhydroxyl compounds,in particular compounds which contain 2-8 hydroxyl groups, andespecially those with a molecular weight of about 800 to about 10,000preferably about 1000 to about 6000 e.g. polyesters, polyethers,polythioethers, polyacetals, polycarbonates and polyesteramides whichcontain at least two and generally 2-8 but preferably 2-4 hydroxylgroups of the kind which are known per se for producing both homogeneousand cellular polyurethanes.

Any suitable polyester which contains hydroxyl groups may be used suchas, for example, the products obtained by reacting polyhydric alcohols,preferably glycols, with the optional addition of trihydric alcohols,with polybasic, preferably dicarboxylic acids. Instead of freepolycarboxylic acids, the corresponding carboxylic acid anhydrides orcorresponding polycarboxylic acid esters of lower alcohols or mixturesof these may be used for preparing the polyesters. The polycarboxylicacids may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic andmay be substituted e.g. with halogen atoms, and/or unsaturated. Thefollowing are given as examples: succinic acid, adipic acid, azelaicacid, suberic acid, sebacic acid, phthalic acid, isophthalic acid,trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acidanhydride, hexahydrophthalic acid anhydride, tetrachlorophthalic acidanhydride, endomethylene tetrahydrophthalic acid anhydride, glutaricacid anhydride, maleic acid, maleic acid anhydride, fumaric acid,dimeric and trimeric fatty acids such as oleic acid, optionally mixedwith monomeric fatty acids, dimethylterephthalate and diethyleneterephthalate. Any suitable polyhydric alcohol may be used such as, forexample, ethylene glycol, propylene-1,2- and -1,3-glycol, butylene-1,4-and -2,3-glycol, hexane-1,6-diol, octane-1,8-diol, neopentyl glycol,cyclohexane dimethanol (1,4-bis-hydroxymethylcyclohexane),2-methyl-propane-1,3-diol, glycerol, trimethylolpropane,hexane-1,2,6-triol, butane-1,2,4-triol, trimethylolethane,pentaerythritol, quinitol, mannitol, and sorbitol, methyl glycoside,diethylene glycol, triethylene glycol, tetraethylene glycol,polyethylene glycols, dipropylene glycol, polypropylene glycols,dibutylene glycol and polybutylene glycols. The polyesters may containsome terminal carboxyl groups. Any suitable polyester of a lactone suchas ε-caprolactone or hydroxycarboxylic acids, e.g. ω-hydroxycaproic acidmay also be used.

Any suitable polyether which contains at least two and generally 2 to 8,preferably 2 or 3 hydroxyl groups known per se and prepared e.g. bypolymerizing epoxides such as, ethylene oxide, propylene oxide, butyleneoxide, tetrahydrofuran, styrene oxide or epichlorohydrin, each withitself, e.g. in the presence of BF₃, or by a reaction of addition ofthese epoxides, optionally as mixtures or successively, to startingcomponents which contain reactive hydrogen atoms such as alcohols oramines, e.g. water, ethylene glycol, propylene-1,3- or -1,2-glycol,trimethylolpropane, 4,4'-dihydroxydiphenylpropane, aniline, ammonia,ethanolamine or ethylenediamine may be used. Sucrose polyethers, e.g.those described in German Auslegeschrift Nos. 1,176,358 and 1,064,938may also be used for the process of the invention. It is frequentlypreferred to use those polyethers which contain predominately primary OHgroups (up to 90% by weight, based on all the OH groups present in thepolyether). Polyethers which have been modified with vinyl polymer, e.g.by polymerization with styrene or acrylonitrile in the presence ofpolyethers (U.S. Pat. Specification Nos. 3,383,351; 3,304,273;3,523,093; and 3,110,695 and German Pat. Specification No. 1,152,536)and polybutadienes which contain OH groups are also suitable.

Any suitable polythioether may be used including the condensationproducts of thiodiglycol with itself and/or with other glycols,dicarboxylic acids, formaldehyde, aminocarboxylic acids or aminoalcohols. The products obtained are polythio mixed ethers, polythioether esters or polythioether ester amides, depending on thecocomponent.

Any suitable polyacetal may be used e.g. the compounds obtained fromglycols, such as diethylene glycol, triethylene glycol,4,4'-dioxethoxy-diphenyldimethylmethane, hexanediol and formaldehyde.Polyacetals suitable for the process according to the invention may alsobe prepared by polymerizing cyclic acetals.

Any suitable hydroxyl polycarbonates of the kind already known per se,may be used such as e.g. those obtained by reacting diols such aspropane-1,3-diol, butane-1,4-diol and/or hexane-1,6-diol, diethyleneglycol, triethylene glycol or tetraethylene glycol with diarylcarbonates such as diphenylcarbonate or phosgene.

Any suitable polyester amide or polyamides may be used including, forexample, the predominately linear condensates which can be obtained frompolyvalent saturated and unsaturated carboxylic acids or theiranhydrides and polyvalent saturated and unsaturated aminoalcohols,diamines, polyamines and mixtures thereof.

Polyhydroxyl compounds which already contain urethane or urea groups aswell as modified or unmodified natural polyols such as castor oil,carbohydrates or starch may also be used. Addition products of alkyleneoxides and phenol formaldehyde resins or of alkylene oxides and ureaformaldehyde resins may also be used according to the invention.

Representatives of these organic compounds having reactive hydrogenatoms which may be used for the process according to the invention aredescribed e.g. in High Polymers, Vol. XVI, "Polyurethanes, Chemistry andTechnology" by Saunders and Frisch, Interscience Publishers, New York,London, Vol. I, 1962, pages 32-42 and pages 44-54 and Vol. II. 1964,pages 5-6 and pages 198-199 and in Kunststoff-Handbuch, Vol. VII,Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 45-71the disclosures of which are incorporated herein by reference.

The non-ionic hydrophillic center may be introduced by includingsuitable non-ionic hydrophillic substances or by a subsequent reaction.

The prepolymers obtained by the usual non-ionic hydrophilic modificationfrequently have a viscosity at 25° C of more than 2000 cP and in somecases up to 100,000 cP or more. In cases where such high viscosities areundesirable for subsequent processes carried out on the product, theviscosity may be lowered to a desirable level by adding low viscosityisocyanates or inert solvents. Furthermore, the length of time of thehardening process may be increased by a combination of such prepolymerswith the usual low viscosity isocyanates.

Non-ionic hydrophilic prepolymers which are particularly preferred areobtained by reacting aromatic polyisocyanates with monofunctionalhydrophilic polyethers based on alcohols and ethylene oxide with amolecular weight of about 500 to 2000. Prepolymers of this kind can beobtained simply by reacting the aromatic polyisocyanates with thehydrophilic polyethers which contain terminal OH groups at roomtemperature or at elevated temperatures and they are characterized bycontaining urethane groups and/or allophanate groups.

The presence of only a low proportion of non-ionic hydrophilic groups issufficient to insure the desired high degree of compatibility of thenon-ionic hydrophilic prepolymers with the aqueous silicate solution.For example, 1% to 2% by weight, based on the prepolymer is sufficient,although the proportion of non-ionic hydrophilic groups is preferably 5%to 25% by weight. In exceptional cases, for example, if the non-ionichydrophilic prepolymers contain comparatively non-reactive isocyanategroups or other end groups, the proportion of non-ionic hydrophilicgroups may be increased to more than 50% by weight.

The prepolymer which has been modified with non-ionic hydrophilic groupsmay, of course, be prepared just before it is mixed with silicatesolution, e.g. conventional hydrophobic prepolymers such as thephosgenation product of an aniline-formaldehyde condensate may be mixedwith a hydrophilic polyether which contains OH or NH groups immediatelybefore it is mixed with waterglass.

The reaction with carboxyl groups or with aminocarbamates is alsoaccompanied by the liberation of CO₂ which acts as a hardener. Carbondioxide is also formed if the process is carried out in the presence ofcatalysts which accelerate carbodiimide formation, such as phospholineoxide. In all these reactions, one advantage of the process of thisinvention is that the carbonic acid formed in most cases diffusesquantitatively and practically instantly into the aqueous phase where iteffects hardening of the silicate solution.

The invention contemplates the use of any suitable aqueous solution ofan alkali metal silicate, containing 20-70% by weight of said alkalimetal silicate, such as, for example, sodium silicate, potassiumsilicate or the like. Such aqueous silicates are normally referred to as"waterglass." It is also possible to use crude commercial-gradesolutions which can additionally contain, for example, calcium silicate,magnesium silicate, borates and aluminates. The Me₂ O:SiO₂ ratio is notcritical and can vary within the usual limits, preferably amounting to4-0.2. Me, of course, refers to the alkali metal. Preferably, sodiumsilicate with a molar ratio of Na₂ O:SiO₂ between 1:1:6 and 1:3.3 isused. If the water content of the inorganic-organic end productinitially obtained by reaction with the organic polyisocyanate isunimportant because it is chemically bound by the water-bindingcomponent as it is harmless or because it can readily be removed bydrying, it is possible to use neutral sodium silicate from which 20 to35% by weight solutions can be prepared. However, it is preferred to use32 to 54% silicate solutions which, only if made sufficiently alkaline,have a viscosity of less than 500 poises at room temperature which isthe limit required to insure problem-free processing. Although ammoniumsilicate solutions can also be used, they are less preferred. Thesolutions can either be genuine solutions or even colloidal solutions.

The choice of the concentration of the aqueous silicate solution isgoverned above all by the required end product. Compact or closed-cellmaterials are preferably prepared with concentrated silicate solutionswhich, if necessary, are adjusted to low viscosity by the addition ofalkali hydroxide. It is possible in this way to prepare 40% to 70% byweight solutions. On the other hand, 20% to 40% by weight silicatesolutions are preferably used for the production of open-celllightweight foams in order to obtain low viscosities, sufficiently longreaction times and low densities. Even in cases where finely dividedinorganic fillers are used in relatively large quantities, 20% to 45% byweight silicate solutions are preferred.

It is also possible to make the silicate solution in situ by using acombination of solid alkali metal silicate and water.

Water-binding components which may be used according to the inventioninclude organic or inorganic water-binding substances which have firstthe ability to chemically combine, preferably irreversibly, with waterand second the ability to reinforce the organic-inorganic end productsof the invention. The most preferred water-binding agents of theinvention, hold the water chemically bound until heated sufficiently, asin a fire. Thus, in a fire the water is released and extinguishes thefire. The term "water-binding component" is used herein to identify amaterial preferably granular or particulate which is sufficientlyanhydrous to be capable of absorbing water to form a solid or gel suchas mortar or hydraulic cement. This component mauy be a mineral orchemical compound which is anhydrous, such as CaO and CaSO₄ but mayexist as a partial hydrate. The water-binding components preferably usedare inorganic materials such as hydraulic cements, synthetic anhydrite,gypsum or burnt lime.

Suitable hydraulic cements are in particular Portland cement,quick-setting cement, blast-furnace Portland cement, mild-burnt cement,sulphate-resistant cement, brick cement, natural cement, lime cement,gypsum cement, pozzolan cement and calcium sulphate cement. In general,any mixture of fine ground lime, alumina and silica that will set to ahard product by admixture of water, which combines chemically with theother ingredients to form a hydrate may be used. The most preferredforms of water-binding agents to be used in accordance with theinvention are those materials which are normally known as cement. Inother words, they are a normally powdered material with which waternormally forms a paste which hardens slowly and may be used to bindintermixed crushed rock or gravel and sand into rockhard concrete. Thereare so many different kinds of cement which can be used in theproduction of the compositions of the invention and they are so wellknown that a detailed description of cement will not be given here.However, one can find such a detailed description in Encyclopedia ofChemical Technology, Volume 4, Second Edition, Published by Kirk-Othmer,pages 684-710, as well as in other well known references in this field.In particular, pages 685-697 of the aforementioned Volume 4, SecondEdition of Kirk-Othmer's Encyclopedia containing a detailed disclosureof the type of cement which may be used in the production of thecompositions of this invention are incorporated herein by reference.

Production of the inorganic-organic compositions according to theinvention is simple. It is merely necessary for the components to cometogether, for example, one may mix the organic polyisocyanate with theaqueous alkali silicate solution, after which the mixture generallyhardens immediately. The mixtures are typical finely divided emulsionsor sols. They are not optically clear, but generally opaque ormilky-white. The subsequent xerosol seems to be preformed in them.

Important advantages obtained according to the invention are the shortmixing time, which amounts to between 2 seconds and at the most about 5minutes when the components are mixed by a discontinuous process, andthe rapid hardening time, which is generally less than 30 minutes.

In commercial production processes, these advantages can result in shortmolding times and hence rapid manufacturing cycles.

The mixture of the components, generally is not stable. The so-called"pot lives," during which the mixtures are processible, are governedabove all by the amount and reactivity of the organic polyisocyanate andby the concentration of the silicate solution. The "pot life" is between0.2 seconds and 2 days, it can be adjusted between 0.2 seconds andseveral hours (i.e., about 4 hours) or it can be between 2 seconds toabout 1 hour. In the case of masked isocyanates which do not containfree --NCO groups, it is even possible to achieve pot lives of severalhours up to about 2 days. Pot lives of from about 1 second to about 20minutes are preferred at these times are most often suitable.

It follows from this that combination of the reactive starting materialsis generally carried out immediately before forming. The polyurea-silicagel composite materials can be produced by previously known techniques,for example, in the same way as cast or foamed polyurethanes employingfor example, a mixer such as is disclosed in U.S. Reissue Pat. No.24,514. If the water-binding component is also included in the reactionmixture it is preferred to use a mixer such as is conventionally used inthe building-construction trade, for example, for making mortar. Thus, amixer with a large ribbon type blender can be used whereby the threecomponents are simultaneously introduced into the mixer and then shortlyafter mixing the reacting components are poured onto a surface or into amold where they are allowed to react to form the inorganic-organiccompositions of the invention. Still further it is possible to simplymix the components in a container for example with a relatively lowspeed mixer as one would use to stir paint and then pour the componentsinto another mold or to allow them to react in the container. It is alsopossible to use a kneader for the mixing of the components. Stillfurther, one may mix the reacting components in an extruder which hasone or more entrance ports so that components may be eithersimultaneously injected and mixed or they may be separately added to theextruder. For example, a premixture of the alkali metal silicatesolution and the organic polyisocyanate may be mixed with thewater-binding component or alternately it is possible to insert thethree components one at a time into the extruder through separate portsand it is even possible to add an accelerator through a fourth port intothe extruder.

It is important, if the water-binding component is present in thereaction mixture, that it be kept separate from the alkali metalsilicate solution until it is time to allow the reaction mixture toreact to completion. Thus, it is possible to mix the three components;namely, the organic polyisocyanate, the alkali silicate solution, andthe water-binding component simultaneously or it is also possible topremix the water-binding component and the organic polyisoycanatecomponent and then add the alkali metal silicate component. It isgenerally undesirable to mix the water-binding component and the alkalimetal silicate component before the organic polyisocyanate is addedbecause this can lead to preliminary solidification of the alkali metalsilicate solution. Thus, it is preferred to either simultaneously mixall three of the essential components or first mix the organicpolyisocyanate with either the alkali metal silicate solution or thewater-binding component and then add the remaining ingredient to themixture.

The quantitative ratios of the components is not critical in theproduction of the polyurea silica gel composite material. This is ofparticular advantage because it means that dosage does not have to beexact even in continuous production through metering devices and mixingchambers. Thus, it is even possible to use heavy-duty metering devicessuch as gear pumps.

The ratios of the essential reactants which lead to theinorganic-organic compositions of the invention may vary, broadlyspeaking, within ranges as follows:

a. from 5-98% by weight of the organic non-ionic hydrophilicpolyisocyanate

b. from 2-95% by weight of an aqueous alkali metal silicate solutioncontaining about 20-70% by weight of said alkali metal silicate based onthe total weight of (a) and (b).

Thus, a preferred combination within the scope of the invention involvesthe reaction of components in the amounts within the following ranges:

a. 10-80% by weight of said organic non-ionic hydrophilicpolyisocyanates, and

b. 20-90% by weight of said aqueous alkali metal silicate solution.

A still more preferred composition is obtained from components in thefollowing ranges:

a. 10-50% by weight of said organic polyisocyanates,

b. 50-90% by weight of said alkali metal silicate solution.

The most preferred ranges of components are as follows:

a. 20-50% by weight of said organic polyisocyanates,

b. 50-80% by weight of said alkali metal silicate solution.

The reactants are preferably mixed at room temperature though anysuitable temperature in the range of -20° C to 80° C may be employed.

The activity of the reaction mixture can be most easily adjusted byadjusting the non-ionic hydrophilic group content.

Products of low silicate content, for example, between 10 and 30% byweight are prepared when it is desired that the organic polymerproperties should be predominant. In these products the silicatefraction reacts as a binding substance with the normally inactivefillers such as chalk, heavy spar, gypsum, anhydrite, clay, kaolin andthe like.

Small quantities of silicate solutions can also be used in cases whereit is required to harden an isocyanate prepolymer with water to form apore-free homogeneous plastic provided said prepolymer containsnon-ionic hydrophilic groups. Since the reaction of NCO-groups withwater is known to be accompanied by the evolution of CO₂, in the absenceof alkali metal silicate water can virtually only be used for theproduction of foams. In the presence of alkali metal silicate, the CO₂formed is absorbed by the silicate. Thus, even in cases where waterglasssolutions are used in standard polyurethane elastomer recipes, it ispossible to prevent the formation of pores through liberated CO₂.Further, the reaction of organic polyisocyanate containing non-ionichydrophilic groups with concentrated alkali metal silicate solutions,which may if desired by alkalized, leads to a product with considerablyreduced pore formation and, providing the quantitative ratios which canbe empirically determined without difficulty are adapted to one another,to a "water-extended" or "water-crosslinked," completely bubble-freematrial. Accordingly, high quality homogenous polyureas can be obtainedby a simple, solvent-free direct process. The required reaction velocitycan readily be adjusted by varying the non-ionic hydrophilic groupcontent.

According to the invention, foam materials with excellent fireresistance is obtained if the sum of inorganic constituents includingfillers is more than 30% by weight by preferably more than 50% byweight, based on the total mixture.

High silicate contents, for example, from 50% to 95% by weight aredesirable in cases where the properties of an inorganic silicatematerial, especially high-temperature stability and relatively completenon-inflammability, are essential requirements. In this case, thefunction of the organic polyisocyanate is that of a non-volatilehardener whose reaction product is a high molecular weight polymer whichreduces the brittleness of the product. By virtue of the elasticizingeffect, organic polyisocyanates are superior to the conventionalacid-based hardeners. The hardening times generally increase withdecreasing ionic group content. However, it is of course, also possibleto use organic polyisocyanates, in combination with acid-liberatinghardeners. In this case, the reaction products of the organicpolyisocyanates with water act mainly as elasticizing components.

Mixtures of organic polyisocyanates and aqueous silicate solutionscontaining more than 30% by weight of water are preferably used for theproduction of thin layers, for example, surface coatings or putties,adhesives, caulks and more particularly, for the production of foams.The production of foams is a preferred embodiment of the invention.

In the production of foams by the process according to the invention, itis also advisable to use expanding or blowing agents. Any suitableblowing agent may be used including, for example, inert liquids boilingat temperatures of from -25° to +50° C. The blowing agents preferablyhave boiling points of from -15° C. to +40° C. The blowing agents arepreferbly insoluble in the silicate solution. Particularly suitableblowing agents are alkanes, alkenes, halogen-substituted alkanes andalkenes or dialkyl ethers, such as for example, saturated or unsaturatedhydrocarbons with 4 to 5 carbon atoms such as isobutylene, butadiene,isoprene, butane, pentane, petroleum ether, halogenated saturated orunsaturated hydrocarbons such as chloromethyl, methylene chloride,fluorotrichloromethane, difluorodichloromethane, trifluorochloromethane,chloroethane, vinyl chloride, vinylidene chloride.Trichlorofluoromethane, vinyl chloride and C₄ -hydrocarbons such asbutane for example, have proved to be the most suitable.

Thus, any suitable highly volatile inorganic and/or organic substancesmay be used as a blowing agent, including those listed above. Additionalsuitable blowing agents are, for example, acetone, ethyl acetate,methanol, ethanol, hexane or diethylether. Foaming can also be achievedby adding compounds which decompose at temperatures above roomtemperature to liberate gases such as nitrogen for example, azocompounds, such as azoisobutyric acid nitrile. Other examples of blowingagents are included for example, in Kunststoff-Handbuch, Volume VII,published by Vieweg and Hochtlen, Car-Hanser-Verlag, Munich 1966, e.g.on pages 108 and 109, 453 to 445 and 507 to 510; but the water containedin the mixture may also function as blowing agent. Fine metal powderssuch as powdered calcium, magnesium, aluminum or zinc may also be usedas blowing agents since they evolve hydrogen in the presence ofwaterglass which is sufficiently alkaline and, at the same time, have ahardening and reinforcing effect.

It has been found that blowing agents which contain fluorine such asthose listed above exhibit a synergistic effect in that they not onlyfunction to foam the reaction mixture but also they have a specialeffect in that they decrease the surface tension of the organic phase.This is important because it makes it possible to obtain high qualityproducts even with relatively small amounts of polyisocyanates.Furthermore, the use of a fluorine containing blowing agent, such as thechloro fluoro alkanes listed above assists in creating a greaterdifferential between the surface tension of the inorganic phase which ishigher and the surface tension of the organic phase.

Thus, the best products of the invention are believed to be the oneswhere the organic phase is the continuous phase and the inorganic phaseis a discontinuous or continuous phase and this may be brought about bythe use of an amount of an organic polyisocyanate which is more than 20%by weight of the portion of the composition based on the organicpolyisocyanate and the alkali metal silicate, but it can be even lessthan 20% by weight where one employes a fluorine containing blowingagent because of the lower surface tension of the organic phase whichleads to the results pointed out above. In other words, it is possibleto get a continuous organic phase with lower amounts of organicpolyisocyanate when one uses a fluorine containing blowing agent.

The blowing agents may be used in quantities of from up to 50% by weightand preferably in quantities of from 2 to 10% by weight, based on thereaction mixture.

Foam can, of course, also be produced with the assistance of inertgases, especially air. For example, one of the two reaction componentscan be prefoamed with air and then mixed with the other. The componentscan also be mixed for example, by means of compressed air so that foamis directly formed, subsequently hardening in molds.

Other substances, such as the emulsifiers, activators and foamstabilizers normally used in the production of polyurethane foams, canalso be added. However, they are generally not necessary. An addition ofsilanes, polysiloxanes, polyethyer polysiloxanes or silyl-nodifiedisocyanates; can intensify the interaction between the two phases.Examples of foam stabilizers are disclosed in U.S. Pat. No. 3,201,372 atColumn 3, line 46 to Column 4, line 5.

Catalysts are often used in the process according to the invention. Thecatalysts used may be known per se, e.g. tertiary amines such astriethylamine, tributylamine, N-methyl-morpholine, N-ethyl-morpholine,N-cocomorpholine, N,N,N,', N' -tetramethyl-ethylenediamine,1,4-diaza-bicyclo-(2,2,2)-octane, N-methyl-N'-dimethylaminoethylpiperazine, N,N,-dimethyl benzylamine,bis-(N,N-diethylaminoethyl)-adipate, N,N-diethyl benzylamine,pentamethyl diethylenetriamine, N,N-dimethyl cyclohexalamine,N,N,N',N'-tetramethyl-1,3-butanediamine, N,N-dimethyl-β-phenylethylamine, 1,2-dimethyl imidazole, 2-methyl imidazole and particularlyalso hexahydrotriazine derivatives.

The following are examples of tertiary amines containing hydrogen atomswhich are reactive with isocyanate groups: triethanolamine,triisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine,N,N-dimethyl-ethanolamine and their reaction products with alkyleneoxides such as propylene oxide and/or ethylene oxide.

Silaamines with carbon-silicon bonds may also be used as catalysts, e.g.those described in German Pat. Specification No. 1,229,290, for example,2,2,4-trimethyl-2-silamorpholine or1,3-diethylaminomethyl-tetramethyldisiloxane.

Bases which contain nitrogen such as tetraalkyl ammoinum hydroxides,alkali metal hydroxides such as sodium hydroxide, alkali metalphenolates such as sodium phenolate or alkali metal alcoholates such assodium methylate may also be used as catalysts. Hexahydrotriazines arealso suitable catalysts.

Organic metal compounds may also be used as catalysts according to theinvention, especially organic tin compounds.

The organic tin compounds used are preferably tin (II) salts ofcarboxylic acids such as tin(II)-acetate, tin(II)-octoate, tin(II)-ethylhexoate and tin(II)-laurate and the dialkyl tin salts of carboxylicacids such as dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tinmaleate or dioctyl tin diacetate.

Other examples of catalysts which may be used according to the inventionand details of the action of the catalysts may be found inKunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen,Carl-Hanser-Verlag, Munich 1966, e.g. on pages 96 to 102.

The catalysts are generally used in a quantity of between about 0.001and 10% by weight, based on the quantity of isocyanate.

Particularly high quality products are obtained by the process accordingto the invention where hardening is carried out at temperatures above80° C, more particularly at temperatures of from 100° C to 200° C.Particularly in the case of combinations of organic polyisocyanates with10% to 40% of NCO-groups and alkali silicate solutions, so much heat isliberated, even in the absence of applied heat, that the water presentbegins to evaporate. Temperatures up to 130° C are reached inside thefoam blocks. The foregoing temperatures are only the preferred ones inthe absence of water-binding components. If water-binding components arepresent then the temperatures are usually lower, in most cases, forinstance, between about 40 and about 100° C.

It would seem that particularly pronounced interactions and aparticularly intimate bond between inorganic and organic polymer aredeveloped under conditions such as these, resulting in the formation ofmaterials which, on the one hand, are as hard as stone but which on theother hand are highly elastic and, hence, highly resistant to impact andbreakage.

If the quantity of heat which is liberated during the reaction betweenthe components is not sufficient to obtain optimum properties, mixingcan readily be carried out at elevated temperatures, for example, attemperatures of from 40° C to 100° C. In special cases, mixing can alsobe carried out under pressure at temperatures above 100° C up to about150° C in a closed container so that expansion occurs, accompanied byfoam formation, as the material issues from the container.

Generally, production of the foams in accordance with the invention iscarried out by mixing the described reaction components together eitherin one stage or in several stages in a batch-type or continuous mixer,and allowing the resulting mixture to foam and harden in molds or onsuitable substrates, generally outside the mixer. The necessary reactiontemperature amounting to between preferably about 0° C and 200° C andmost preferably to between 40° C and 130° C, can either be achieved bypreheating one or more reaction components before the mixing process orby heating the mixer itself or by heating the reaction mixture preparedafter mixing. Combinations of these or other procedures for adjustingthe reaction temperature are of course, also suitable. In most cases,sufficient heat is generated during the reaction itself so that, afterthe beginning of the reaction or foaming, the reaction temperature canrise to levels about 100° C.

For any given recipe, the properties of the resulting foams, forexample, their moist density, is governed to some extent by theparameters of the mixing process, for example, the shape and rotationalspeed of the stirrer, the shape of the mixing chamber etc., and also bethe reaction temperature selected for densities foaming. The moist,fresh foam can have a density of approximately from 0.01 to 1.3 g/cc,although in general the moist fresh foam is obtained with densities offrom 0.01 to 0.2 g/cc. The dried foams can have cloeed or open cells,although in most cases they are largely made up of open cells and havedensities of from 0.005 to 0.6 g/cc. Where the water-binding componentis present, densities of 0.02 and 0.8 g/cc are preferred. Especiallypreferred are lightweight foams with denisities from 0.01 to 0.2 g/cc.

Lightweight foams having a density from 0.01 to 0.08 are of specialinterest.

In case of high amounts of inorganic material these foams are combininggood flame resistance, insulating, insulating properties and low costsof the starting materials.

Regarding the low density of the foams compression strength is not veryhigh.

A mixture of about equal parts of alkali metal silicate andpolyisocyanate or an excess of alkali metal silicate is preferred. Waterbinding fillers are usually omitted whereas favourably salts ofphosphoric acid are added to improve the hardening process of the alkalimetal silicate as well as the fire resistance of the foam material.

In combination with expanded clay -- in this case the foam materialplays the part of a binding agent -- high concrete is obtained which canfor example be used as panels in the construction field.

By virtue of the behavoir of the reaction mixtures, the processaccording to the invention is provided with a number of potentialutilities either as porous or homogeneous materials, and, accordingly, afew fields of application are outlined by way of example in thefollowing. The possiblity of leaving the water present in the hardenedmixtures either as a required constituent of the foam, or of protectingthe foam against the elimination of water by suitably coating orcovering the foam with a water impermeable layer, or by removing all orsome of the water by suitable drying techniques, for example, in aheating cabinet, or oven hot air, infrared heating, ultra-sonic heatingor high-frequency heating, can be selected from case to case to suit theparticular requirements of application.

The reaction mixture containing the blowing agent can be coated forexample, onto any given warm, cold or even IR- or HF-irradiatedsubstrates, or after passing through the mixer, can be sprayed withcompressed air or even by the airless process onto these substrates onwhich it can foam and harden to give a filling or insulating coating.The foaming reaction mixture can also be molded, cast orinjection-molded in cold or heated molds and allowed to harden in thesemolds, whether relief or solid or hollow molds, if desired bycentrifugal casting at room temperature or temperatures of up to 200° Cand if desired under pressure. In this respect, it is quite possible touse strengthening elements, whether in the form of inorganic and/ororganic or metallic wires, fibers, webs, foams, woven fabrics,skeletons, etc. This can be done for example, by the fiber-matimpregnating process or by processes in which reaction mixtures andstrengthening fibers are applied together to the mold, for example, bymeans of a spray unit. The moldings obtainable in this way can be usedas structural elements, for example, in the form of optionally foamedsandwich elements produced either directly or subsequently by laminationwith metal, glass, plastics, etc., in which case the favorable flamebehavior of the foams in their moist or dry foam is of particularadvantage. However, they can also be used as hollow bodies, for example,as containers for products that may have to be kept moist or cool, asfilter materials or exchangers, as supports for catalysts or activesubstances, as decorative elements, as parts of furniture and as cavityfillings. They can also be used as high-stress lubricants and coolantsor as carriers therefor, for example, in the extrusion of metals. Theycan also be used in the field of pattern and mold design, and also inthe production of molds for casting metals.

In one preferred procedure, foaming is directly accompanied byhardening, for example, by preparing the reaction mixture in a mixingchamber and simultaneously adding the readily volatile blowing agent,for example, dichlorodifluoromethane, trichlorofluoromethane, butane,isobutylene or vinyl chloride, so that, providing it has a suitabletemperature, ture, the reaction mixture issuing from the mixing chambersimultaneously foams through evaporation of the blowing agent andhardens to its final foam form under the effect of the organicpolyisocyanate, said foam optionally containing emulsifiers, foamstabilizers and other additives. In addition, the initially still thinlyliquid reaction mixture can be expanded into a foam by the introductionof gases optionally under pressure such as air, methane, CF₄, noblegases, the resulting foam being introduced into the required mold andhardened therein. Similarly, the silicate- or organic polyisocyanatesolution optionally containing foam stabilizers such as surfactants,foam formers, emulsifiers and, optionally, other organic or inorganicfillers or diluents, may initially be converted by blowing gas into afoam and the resulting foam subsequently mixed in the mixer with theother components and optionally with the hardener and the resultingmixture allowed to harden.

In one preferred procedure, a solution of the organic polyisocyanate inliquid expanding or blowing agent is mixed with the optionally preheatedaqueous alkali silicate solution and thus hardened while foaming.

Instead of blowing agents, it is also possible to use inorganic ororganic finely divided hollow bodies such as expanded hollow beads ofglass or plastics, straw and the like, for producing foams.

The foams obtainable in this way can be used either in their dry ormoist form, if desired after a compacting or tempering process,optionally carried out under pressure, as insulating materials, cavityfillings, packaging materials, building materials with outstandingresistance to solvents and favorable flame behavior. They can also beused as lightweight bricks or in the form of sandwhich elements, forexample, with metal covering layers, in house, vehicle and aircraftconstruction.

The reaction mixtures can also be dispersed in the form of droplets, forexample, in petrol, or foamed and hardened during a free fall or thelike, resulting in the formation of foam beads.

It is also possible to introduce into the foaming reaction mixtures,providing they are still free-flowing, organic and/or inorganic foamableor already foamed particles, for example, expanded clay, expanded glass,wood, popcorn, cork, hollow beads of plastics, for example, vinylchloride polymers, polyethylene, styrene polymers or foam particlesthereof or even, for example, polysulphone, polyepoxide, polyurethane,ureaformaldehyde, phenol formaldehyde, polyimide polymers, or to allowthe reaction mixtures to foam through interstitial spaced in packedvolumes of these particles, and in this way to produce insulatingmaterials which are distinguished by excellent flame behavior.Combinations of expanded clay, glass, or slate with the reactionmixtures according to the invention, are especially preferred.

When a mixture of aqueous silicate solutions optionally containinginorganic and/or organic additives and the organic polyisocyanates hassimultaneously added to it at a predetermined temperature the blowingagent which is capable of evaporation or of gas formation at thesetemperatures, for example a (halogenated) hydrocarbon, the initiallyliquid mixture formed can be used not only for producing uniform foamsor non-uniform foams containing foamed or unfoamed fillers, it can alsobe used to foam through any given webs, woven fabrics, lattices,structural elements or other permeable structures of foamed materials,resulting in the formation of composite foams with special properties,for example, favorable flame behavior, which may optionally be directlyused as structural elements in the building, furniture or vehicle andaircraft industries.

The foams according to the invention can be added to soil in the form ofcrumbs, optionally in admixture with fertilizers and plant-protectionagents, in order to improve its agrarian consistency. Foams of highwater content can be used as substrates for propagating seedlings,cuttings and plants or cut flowers. By spraying the mixtures ontoimpassable or loose terrain, for example, sand dunes or marshes, it ispossible to obtain effective consolidation which soon becomes passableand offers protection against erosion.

It is also advantageous to spray the proposed reaction mixtures onto anarticle to be protected in the event of fire or accident, the waterpresent being unable to run down or prematurely evaporate on the surfaceof the structure to be protected, so that particularly effectiveprotection against fire, heat or radiation is obtained because thehardened mixture, providing it still contains water, cannot be heated totemperatures appreciably above 100° C and it also adsorbs IR or nuclearradiation.

By virtue of their favorable spray properties, the mixtures can formeffective protective walls and protective layers in the event of miningaccidents and also in routine work, for example, by spraying them ontowoven fabrics, other surfaces, latticies or even only onto walls. Oneparticular advantage in this respect is that hardening is quicklyobtained.

Similarly, the foaming mixtures can be used in construction engineering,in civil engineering and road building for erecting walls, igloos, sealsfor filling joints, plastering, flooring, insulation, decoration and asa coating, screed and covering material. They can also be considered foruse as adhesives or mortars or as casting compositions, optionallyfilled with inorganic or organic fillers.

Since the hardened foams obtained by the process according to theinvention can show considerable porosity after drying, they are suitablefor use as drying agents because they can absorb water. However, theycan also be charged with active substances or used as catalyst supportsor filters and absorbents.

Auxiliaries which may if desired, be used in or subsequently introducedinto the reaction mixture, such as emulsifiers, surfactants,dispersants, ordorants, hydrophobizing substances, enable the propertyspectrum of the foams in their moist or dry form to be modified asrequired.

On the other hand, the foams can be subsequently lacquered, metallized,coated, laminated galvanized, subjected to vapor deposition, bonded orflocked in their moist or dry form or in impegnated form. The moldingscan be further processed in their moist or dried form, for example, bysawing, milling, drilling, planing, polishing and other machiningtechniques.

The optionally filled moldings can be further modified in theirproperties by thermal aftertreatment, oxidation processes, hot-pressing,sintering processes or surface melting or other consolidation processes.

Suitable mold materials include inorganic and/or organic foamed orunfoamed materials such as metals, for example, iron, nickel, finesteel, lacquered or, for example, tefloncoated aluminum, poreclain,glass, wood, plastics such as PVC, polyethylene, epoxide resins, ABS,polycarbonate, etc.

The foams obtainable in accordance with the invention can besurface-treated or, where they are in the form of substantiallypermeable structures, for example, substantially open-cell foams orporous materials, can even be treated by centrifuging, vacuum treatment,blowing air through or by rinsing with (optionally heated) liquids orgases which remove the water present, such as methanol, ethanol,acetone, dioxan, benzene, chloroform and the like, or dried with air,CO₂, or super heated steam. Similarly, the moist or dry moldings canalso be aftertreated by rinsing or impregnating with aqueous ornon-aqueous acid, neutral or basic liquids or gases, for example,hydrochloric acid, phosphoric acid, formic acid, acetic acid, ammonia,amines, organic or inorganic salt solutions, lacquer solutions,solutions of polymerizable or already polymerized monomers, dyesolutions, galvanizing baths, solutions of catalysts or catalystpreliminary stages, odorants and the like.

The new composite materials are particularly suitable for use asstructural materials because they show tensile and compressive strength,are tough, rigid and at the same time elastic, show high permanentdimensional stability when hot and are substantially non-inflammable.

The excellent heat insulating and sound insulating capacity of thesefoams should also be mentioned which, together with their excellent fireresistance and heat resistance, opens up possibilities for their usesfor insulating purposes.

Thus, it is possible, for example, to produce high quality lightweightstructural panels either by continuously cutting or sawing foamed blocksinto corresponding panels or by foaming panels of this kind and, inparticular, complicated moldings in molds, optionally under pressure. Itis also possible by adopting a suitable procedure to produce moldingwith an impervious outer skin.

When a technique of foaming in the mold under pressure is employed,molded parts with dense marginal zones and completely non-porous smoothsurfaces can be obtained.

However, the process according to the invention is particularly suitablefor in situ foaming on the building site. Thus, any types of hollowmold, of the kind made by formwork in the usual way, can be cast orfilled with foam.

The reaction mixture can also be used to fill cavities, gaps, cracks,giving a very firm bond between the joined materials. Insulatinginternal plasters can also be readily produced by spraying on thereaction mixture.

In many cases, the materials obtained can be used instead of wood orhard-fiber boards. They can be sawed, rubbed down, planed, nailed,drilled, milled and in this way, can be worked and used in a number ofdifferent ways.

Very brittle lightweight foams of the kind which can be obtained forexample, by having a very high silicate content or by combination withequally brittle organic polymers, can readily be converted by crushingin suitable machines into dustfine powders which can be used for anumber of different purposes as organically-modified silica fillers.Organic-modification provides effective surface interaction withpolymers and, in some cases, also a certain degree of surfacethermoplasticity which makes it possible to produce high quality moldingcompositions on which topochemical surface reaction can be carried outby the addition of crosslinking agents.

Fillers in the form of particulate or powdered materials can beadditionally incorporated into the mixtures of organic polyisocyanatesand alkali silicates for a number of applications.

Suitable fillers include solid inorganic or organic substances, forexample, in the form of powders, granulate, wire, fibers, dumb bells,crystallites, spirals, rods, beads, hollow beads, foam particles, webs,pieces of woven fabric, knit fabrics, ribbons, pieces of film, etc., forexample, of dolomite, chalk, alumina, asbestos, basic silicas, sand,talcum, iron oxide, aluminum oxide and oxide hydrate, zeolites, calciumsilicates, basalt wool or powder, glass fibers, C-fibers, graphite,carbon black, Al-, Fe-, Cu-, Ag- powder, molybdenum sulphite, steelwool, bronze or copper cloth, silicon powder, expanded clay particles,hollow glass beads, glass powder, lava and pumice particles, wood chips,sawdust, cork, cotton, straw, jute, sisal, hemp, flax, rayon, popcorn,coke, particles of filled or unfilled, foamed or unfoamed, stretched orunstretched organic polymers including plastics and rubber waste. Of thenumber of suitable organic polymers, the following, which can be presentfor example, in the form of powders, granulate, foam particles, beads,hollow beads, foamable or unfoamed particles, fibers, ribbons, wovenfabrics, webs, etc., are mentioned purely by way of example:polystyrene, polyethylene, polypropylene, polyacrylonitrile,polybutadiene, polyisoprene, polytetrafluoroethylene, aliphatic andaromatic polyesters, melamine-urea or phenol resins, polyacetal resins,polyepoxides, polyhydantoins, polyureas, polyethers, polyurethanes,polyimides, polyamides, polysulphones, polycarbonates, and, of course,any copolymers as well. Inorganic fillers are preferred.

Generally, the composite materials according to the invention can befilled with considerable quantities of fillers without losing theirvaluable property spectrum. The amount of fillers can exceed the amountof the components (a), (b) and (c). In special cases theinorganic-organic composition of the present invention acts as a binderfor such fillers.

In cases where higher amounts of fillers are used it may be advisable toadd water in order to obtain sufficient working properties, coarsefillers can be used in wet form, powdered fillers such as e.g. chalk,alumina, dolomite, calcium hydroxide, magnesium carbonate, calciumcarbonate can be used also as an aqueous suspension.

Products of low silicate content are particularly suitable for theproduction of quick-hardening high quality surface coating which showoutstanding adhesion and resistance to abrasion, and for the productionof elastomers of high strength and high modulus.

For applications such as these, it is preferred to useisocyanato-prepolymer ionomers of low isocyanate content, for example,less than 5% or even prepolymers which have masked isocyanate groups. Itis possible in this way to obtain mixtures with long pot life which canalso be applied in the form of thin layers gradually hardening withtime.

If only a small amount of CO₂ is liberated (by correct adjustment ofproportions and activity) a pasty or doughy plastic material which canbe formed in any way is obtained with partial hardening, which isaccompanied by an increase in viscosity. This material can be formed andhardened at a later stage, for example, by drying in air or by heating.

Such a two-stage or multi-stage hardening process is of particularinterest so far as processing as a putty, trowelling composition,gap-filling compound, mortar and the like, is concerned. In the firststage of this hardening process, for example, there is a rapid evolutionof CO₂ (for example by the reaction of NCO-groups with water) whichconverts the inorganic/organic composite material into a plastic orthermoplastic processible form, hardening taking place in a second,slower hardening stage, for example, through the hydrolysis of a highmolecular weight or low molecular weight ester.

The thermoplastic intermediate stage can also be processed by injectionmolding, extrusion or kneading.

In many cases, these intermediate stages can also be mixed with water,organic solvents, plasticizers, extending agents, fillers and thusmodified and applied in a number of different ways.

The materials according to the invention are also suitable for use asimpregnating agents for finishing fibers, for which purpose it ispossible both to use completed mixtures of the organic and of thesilicate component, and to apply a two-bath treatment. Accordingly, thecomponent with the better adhesion, i.e. the prepolymer component, ispreferably initially applied to organic material, and the silicatecomponent to inorganic material.

In addition, it is possible, for example by extruding the mixturesthrough dies or slots, to produce fibers and films which can be used forexample, for the production of synthetic non-inflammable paper or forthe production of webs.

The foam material according to the invention is capable either ofabsorbing water and/or water vapor or of affording considerableresistance to the eiffusion of water and/or water vapor, depending onthe composition and structure of the material.

The foam material according to the invention opens up new possibilitiesin the fields of underground and surface engineering and in theproduction of finished parts and elements.

The following are mentioned as examples of the possibilities ofapplication: the manufacture of wall cements, for prefabricatedbuildings, sand molds, roller shutter castings, window-sills, railroadand underground sleepers, curbstones, stairs, the filling of joints byfoaming and the backfilling of ceramic tiles by foaming.

The foam material may also advantageously be used for binding gravel andmarble chips, etc; decorative panels can be obtained in this way whichcan be used, for example, as facades.

The invention will now be described in more detail with the aid ofexamples.

EXAMPLES

Preparation of the nonionic-hydrophilic prepolymers Starting materials:

I. polyisocyanate component: Diisocyanatodiphenylmethane is distilledfrom a crude phosgenation product of an aniline/formaldehyde condensateuntil the distillation residue has a viscosity at 25° C of 400 cP.(Dinuclear content: 45.1% by weight, trinuclear content: 22.3% byweight, content in higher nuclear polyisocyanates: 32.6% by weight) NCOcontent: 30% to 31% by weight.

Ii. nonionic-hydrophilic component:

P 1. polyethylene oxide monohydric alcohol, molecular weight 1145,initiated on n-butaneol

P 2. polyethylene oxide monohydric alcohol, molecular weight 782,initiated on n-butanol

P 3. polyethylene oxide monohydric alcohol, molecular weight 1432,initiated on n-butanol

P 4. polyethylene oxide monohydric alcohol, molecular weight 1978,initiated on n-butanol

P 5. polyethylene oxide glycol, molecular weight 614, initiated onpropylene glycol

P 6. polyethylene oxide trihydric alcohol, molecular weight 680,initiated on trimethylol propane

P 7. polyethylene oxide trihydric alcohol, molecular weight 300,initiated on trimethylol propane.

P 8. polypropylene oxide polyethylene oxide glycol, molecular weight4,000, initiated on propylene glycol.

Experimental Procedure:

Polyisocyanate component (I) and nonionic-hydrophilic polyethercomponent (II) are combined and reacted together at 80° C with stirringuntil a homogeneous prepolymer with constant NCO content is obtained.

Prepolymers of this kind are completely stable for many months at roomtemperature and undergo practically no change in their NCO content.

    ______________________________________                                                                   Re-                                                Pre-                       action                                                                              NCO                                          poly-                      time  (% by  Viscosity                             mer    I       II          (h)   weight)                                                                              cP/25° C                       ______________________________________                                        O     500 g    50 g  P 1   1     27.1   650                                   A      80 kg   16 kg P 1   8     24.6   1300                                  B     500 g    250 g  P 1  1     18.7   12,000                                C     500 g    500 g  P 1  1     12.8   15,000                                D     500 g    1000 g  P 1 1     --     solid                                 E     500 g    50 g  P 2   1     27.1   650                                   F     500 g    100 g  P 2  1     23.5   700                                   G     500 g    50 g  P 3   1     24.9   700                                   H     500 g    50 g  P 4   1     27.5   300                                   I     500 g    50 g  P 5   1     26.4   400                                   J     500 g    50 g  P 6   1     26.1   5000                                  K     500 g    100 g  P 6  1     24.1   15,000                                L     500 g    250 g  P 6  1     --     solid                                 M     500 g    50 g  P 7   1     23.5   300                                   N     500 g    100g  P 8   1     25.7   1200                                  ______________________________________                                    

EXAMPLE 1

450 g of Prepolymer A

60 g of trichlorofluoromethane

450 g of sodium waterglass (44% solids, molecular weight ratio Na₂ O :SiO₂ = 1:2)

5 g of amine catalyst (consisting of 75% by weight ofN,N-dimethylaminoethanol and 25% by weight of diazabicyclooctane)

4 g of stabilizer (polyether polysiloxane of Example 1 of U.S. Pat. No.3,629,390, Column 12, lines 6-13).

The mixture of waterglass, amine catalyst and foam stabilizer are addedto the nonionic-hydrophilic prepolymer A which has been diluted withtrichlorofluoromethane. The whole reaction mixture is then vigorouslymixed for 15 seconds, using a high speed stirrer, and then poured outinto paper packets. The foaming process begins after 28 seconds and iscompleted after 40 seconds. The temperature of the reaction mixtureincreases during the expanding process and continues after the foamingmass has solidified, reaching a temperature of about 80° C. A tough,finely porous foam with a regular cell structure is obtained. Initially,the foam contains water but on drying it loses about 10% by weightwithout undergoing any dimensional change. Samples may be removed fromthe foam and the properties determined after 3 hours' tempering at 120°C.

    ______________________________________                                        Density:            15 kg/m.sup.3                                             Compression strength:                                                                            0.22 kp/cm.sup.2                                           Change in Volume (5 h/180° C)                                                              0%                                                        Proportion of open cells:                                                                         97%                                                       Coefficient of thermal                                                         conductivity      0.035 kcal/m/h/degrees                                     Combustibility according to                                                    ASTM D 1692-68    SE (self extinguishing)                                    Resistance to bending in                                                       the heat:         119° C                                              ______________________________________                                    

EXAMPLE 2

450 g of prepolymer A

60 g of trichlorofluoromethane

60 g of red phosphorus (powder)

450 g of waterglass according to Example 1

5 g of amine catalyst according to Example 1

1.5 g of stabilizer according to Example 1

The procedure is the same as in Example 1 except that the red phosphorusis first emulsified in the solution of prepolymer A intrichlorofluoromethane. The reaction mixture is vigorously stirred for15 seconds and then poured out. It begins to foam after 22 seconds andsolidifies after 56 seconds.

Samples may be removed from the resulting finely porous foams and thefollowing properties determined after 3 hours' drying at 120° C:

    ______________________________________                                        Density:           18 kg/cm.sup.3                                             Compression strength:                                                                           0.23 kp/cm.sup.2                                            Change in Volume                                                               (5 h/180° C)                                                                             0%                                                         Combustibility according                                                       to ASTM D 1692-68                                                                              SE (self extinguishing)                                     Small burner test according                                                    to DIN provisional standard                                                   53 438           K 1 (62 mm) / F 1 (97 mm)                                                      (normally combustible)                                     ______________________________________                                    

EXAMPLE 3

    ______________________________________                                        450 g of Prepolymer A                                                          60 g of chlorinated paraffin mixture                                         1.5 g of stabilizer according to Example 1                                                              Component I                                         100 g of trichlorofluoromethane                                               450 g of waterglass according to Example 1                                     5 g of amine catalyst according to                                                                     Component II                                           Example 1                                                                  120 g of calcium hydrogen phosphate                                           ______________________________________                                    

Each component is vigorously stirred to mix its constituents before theexperiment and the two components are then stirred together for 15seconds and the resulting mixture poured out into a paper packet. Thefoaming process begins after 27 seconds and is completed after 80seconds. The resulting tough, finely porous foam is found to have aregular pore structure and after drying (3 hours at 120° C) has adensity of 19.1 kg/m³. This inorganic-organic foam is self-extinguishingaccording to ASTM D 1692-68 and in the samm burner test according to DINprovisional standard 53 438 it is normally combustible.

EXAMPLE 4

    ______________________________________                                        100 g of Prepolymer A                                                                                  Component I                                           20 g of trichloromethane                                                     150 g of waterglass according to                                                 Example 1                                                                  1.5 g of triethylamine                                                        0.2 g of emulsifier, the sodium salt                                             of a sulphochlorinated paraffin                                                                     Component II                                            mixture C.sub.10 -C.sub.14                                                 ______________________________________                                    

Each of the two components is vigorously mixed on its own and the twocomponents are then vigorously stirred together with a high speedstirrer for 15 seconds and the resulting mixture is poured out into apaper packet. The reaction mixture begins to foam after 36 seconds andsolidifies after 30 seconds.

The resulting tough, elastic, inorganic-organic foam had a fine, regularpore structure and without drying has a density of 50 kg/m³.

EXAMPLE 5

    ______________________________________                                        100 g of Prepolymer B                                                                                   Component I                                          20 g of trichlorofluoromethane                                               150 g of waterglass according to Example 1                                    1.5 g of triethylamine                                                        0.2 g of emulsifier according to Example 1                                    ______________________________________                                    

The inorganic-organic foam is produced according to the process ofExample 4. It is a tough, elastic product which is finely porous with aregular cell structure and without drying it has a density of 45 kg/m³.

EXAMPLE 6

    ______________________________________                                        100 g of Prepolymer O                                                                                   Component I                                          20 g of trichlorofluoromethane                                               150 g of waterglass according to                                                 Example 1                                                                  2.0 g of N,N',N"-(ω-dimethylamino-n-propyl)                                                       Component II                                           hexahydrotriazine                                                          2.0 g of stabilizer (polyether poly-                                             siloxane) of Example 1                                                     ______________________________________                                    

The foam is produced by the process of Example 4. A tough, elastic,finely porous inorganic-organic foam which had a density of 20 kg/m³without drying is obtained.

EXAMPLE 7

    ______________________________________                                        450 g of Prepolymer A                                                                                   Component I                                          4 g of stabilizer according to Example 1                                     150 g of waterglass according to Example 1                                                              Component II                                         4 g of amine catalyst according to Example 1                                 ______________________________________                                    

Production of the inorganic-organic foam from components I and II iscarried out as in Example 1.

A finely porous, tough, lightweight foam blown up with carbon dioxide isobtained. It has a regular cell structure and without drying has adensity of 26.4 kg/m³.

The fire characteristics are inferior to those of foams which are beenblown up with trichlorofluoromethane.

EXAMPLE 8

    ______________________________________                                        450 g of Prepolymer A                                                                                   Component I                                          4 g of stabilizer according to Example 1                                     450 g of waterglass according to Example 1                                                              Component II                                         4 g of amine catalyst according to Example 1                                 ______________________________________                                    

Mixing of the components is carried out as in Example 7. The materialobtained is only slightly foamed and has a plastic consistency. Whenhardened by heat or prolonged storage it solidifies to a rock hard,elastic mass.

EXAMPLE 9

    ______________________________________                                        450 g of Prepolymer A                                                          4 g of stabilizer according to Example 1                                                               Component I                                          80 g of trichlorofluoromethane                                               200 g of quick setting cement                                                 450 g of waterglass according to Example 1                                                              Component II                                         3 g of amine catalyst according to Example 1                                 ______________________________________                                    

Each of the two components is first vigorously stirred to mix itsconstituents and the two components are then mixed together for 15seconds with the aid of a high speed stirrer and the resulting mixtureis poured into a sample packet. The reaction mixture begins to foamafter 29 seconds and is solidified after 180 seconds. A finely porousfoam with a density of 28.6 kg/m³ is obtained.

EXAMPLE 10

    ______________________________________                                        450 g of Prepolymer A                                                          4 g of stabilizer according to Example 1                                                               Component I                                          80 g of trichlorofluoromethane                                               200 g of quick setting cement                                                 450 g of waterglass according to Example 1                                     3 g of amine catalyst according to Example 1                                                           Component II                                        200 g of quick setting cement                                                 ______________________________________                                    

The inorganic-organic foam is produced from components I and II asdescribed in Example 9. The stirring time is 15 seconds. The reactionmixture begins to foam after 30 seconds and is solidified after 250seconds.

The finely porous foam had a density of 42.8 kg/m³ without drying.

EXAMPLE 11

    ______________________________________                                        450 g Prepolymer A                                                             60 g of trichlorofluoromethane                                                                         Component I                                          4 g of stabilizer according to Example 1                                     450 g of waterglass according to Example 1                                     4 g of amine catalyst according to Example 1                                                           Component II                                         10 g of vermiculite                                                          ______________________________________                                    

Each of the two components I and II is first vigorously stirred on itsown to mix its constituents and the two components are then vigorouslymixed together. A foam with a density of 31 kg/m³ in which thevermiculite is uniformly distributed is obtained after foaming andhardening.

EXAMPLE 12

A mixture of 450 parts by weight of waterglass according to Example 1and 1 part by weight of amine catalyst according to Example 1 isintroduced into a pressure vessel having a stirrer on the polyol side ofa commercial type H 100 K (Maschinenfabrik Hennecke GmbH) foamingmachine of the kind conventionally used for producing polyurethanefoams. A mixture of 450 parts by weight of prepolymer A, 4 parts byweight of stabilizer according to Example 1 and 150 parts by weight oftrichlorofluoromethane is introduced into a pressure vessel having astirrer on the isocyanate side.

The output rate is adjusted to 6050 g/min on the polyol side and 8040g/min on the isocyanate side. The components are mechanically mixed inthe HK mixing head by the known technique employed for polyurethanerigid foam.

The resulting reaction mixture begins to foam after 3 seconds andsolidifies after 146 seconds with evolution of heat.

Foam blocks measuring 60 × 60 × 60 cm³ which have an average density of17 kg/m³ are produced by this method. The tough-elasticinorganic-organic foam has a regular fine cell structure and isdimensionally unaltered even after 5 hours at 180° C.

It is to be understood that the foregoing Examples are given for thepurpose of illustration and that any other suitable polyisocyanate,polyol, alkali metal silicate or the like can be substituted thereinprovided the teachings of this disclosure are followed.

It is to be understood that any of the components and conditionsmentioned as suitable herein can be substituted for its counterpart inthe foregoing examples and that although the invention has beendescribed in considerable detail in the foregoing, such detail is solelyfor the purpose of illustration. Variations can be made in the inventionby those skilled in the art without departing from the spirit and scopeof the invention except as it may be limited by the claims.

What is claimed is:
 1. An inorganic-organic composition obtained byreacting a mixture ofA. from 5-98% by weight of an organic,non-ionic-hydrophilic polyisocyanate prepared by reacting an excess ofan organic polyisocyanate with an organic hydrophilic compoundcontaining at least one group which is reactive with isocyanate groups,and B. from 2-95% by weight of an aqueous alkali metal silicate solutioncontaining about 20-70% by weight of alkali metal silicate based on theweight of said aqueous solution,the percents by weight of (A) and (B)based on the total weight of (A) and (B), said composition being asolid/solid xerosol.
 2. The composition of claim 1, wherein said organichydrphilic compound is selected from the group consisting of hydrophilicpolyethers, aliphatic polycarbonates, hydrophilic polyesters, andmixtures thereof.
 3. The composition of claim 1, wherein thenon-ionic-hydrophilic polyisocyanate is prepared by at least partiallyreacting an organic polyisocyanate with a polyether which contains atleast 10% by weight of ethylene oxide.
 4. The composition of claim 1,wherein the aqueous silicate solution contains 32-54% by weight silicateand the ratio by weight of polyisocyanate to silicate is from 70:30 to20:80.
 5. The composition of claim 1, wherein an inert liquid boiling attemperatures from -25° C to +50° C is included in the reaction mixtureas a blowing agent in a quantity of up to 50% by weight and the reactionmixture is allowed to react to completion while foaming.
 6. Thecomposition of claim 1 in which the average transverse diameter of thedispersed phase is between 20 nm and 2 microns.
 7. The composition ofclaim 6 wherein the said avererage diameter is between 50 nm and 700 nm.8. The composition of claim 6, wherein both phases are coherent.
 9. Thecompostion of claim 6, which contains an inorganic or organicparticulate or powdered filler material.
 10. The composition of claim 6,which contains glass fibers.
 11. The composition of claim 1, whereinsaid composition is based on:A. 10-80% by weight of said organicpolyisocyanate, and B. 20-90% by weight of said aqueous alkali metalsilicate solution.
 12. The composition of claim 11 wherein the reactionmixture contains a foam stabilizer.
 13. The composition of claim 11wherein the reaction mixture contains an emulsifier agent.
 14. Thecomposition of claim 11, wherein the mixture contains an inert inorganicparticulate or fibrous filler material.
 15. The composition of claim 11,wherein the mixture contains an inert organic particulate or fibrousfiller material.
 16. The composition of claim 11, wherein the mixturecontains an organic compound containing hydrogen atoms which arereactive with isocyanate groups.
 17. The composition of claim 11,wherein the alkali metal silicate is sodium silicate in which the molarratio of Na₂ O:SiO₂ is within the range of 1:1.6 and 1:3.3.
 18. Thecomposition of claim 11, wherein said composition is based on.A. 10-50%by weight of said organic polyisocyanate, and B. 50-90% by weight ofsaid alkali metal silicate solution.
 19. The composition of claim 11,wherein said composition is based on:A. 20-50% by weight of said organicpolyisocyanate, and B. 50-80% by weight of said alkali metal silicatesolution.
 20. The foamed composition of claim 11, wherein the mixturecontains a blowing agent.
 21. The foamed composition of claim 20,wherein the blowing agent is a halogenated hydrocarbon with a boilingpoint below 100° C.
 22. The compositon of claim 11, wherein the mixturecontains an activator which accelerates the reaction of isocyanategroups with water.
 23. The composition of claim 22, wherein theactivator is a tertiary amine.
 24. The composition of claim 11, whereinthe mixture contains an inorganic water binding component, said waterbinding component being capable of absorbing water to form a solid orgel.
 25. The composition of claim 24, wherein the water bindingcomponent is a hydraulic cement, synthetic anhydride, gypsum or burntlime.
 26. A process for producing an inorganic-organic composition, saidcomposition being a solid/solid xerosol, said process comprisingreacting:A. from 5-98% by weight of an organic, non-ionic-hydrophilicpolyisocyanate prepared by reacting an excess of an organicpolyisocyanate with an organic hydrophilic compound containing at leastone group which is reactive with isocyanate groups, and B. from 2-95% byweight of an aqueous alkali metal silicate solution containing about20-70% by weight of an alkali metal silicate based on the weight of saidaqueous solution,the percents by weight of (A) and (B) based on a totalweight of (A) and (B).
 27. The process of claim 26, wherein said organichydrophilic compound is selected from the group consisting ofhydrophilic polyethers, aliphatic polycarbonates, hydrophilicpolyesters, and mixtures thereof.